Several recent high-profile acts of violence have drawn a great deal of public attention and incited calls for research into potential interventions and preventive measures. Rising public awareness of mental health issues and their contribution to crime and violence echoes prominent, ongoing efforts dedicated to increasing brain research and its translation to better behavioral and mental health outcomes. This has led NIH to issue the recent Program Announcement PA-13-363 Research on Health Determinants and Consequences of Violence and its Prevention, Particularly Firearm Violence. Youth prone to serious antisocial behavior demonstrate high rates of mental health disorders. Failing to employ effective treatment for youth involved in the juvenile justice can contribute to cyclical patterns of poor outcomes including substance abuse, criminal recidivism, and worsening mental health problems. Adolescence is a time of substantial neurodevelopment and neuroplasticity. Evidence-based treatment, applied during this critical period, may be particularly effective at improving developmental trajectories in high-risk youth. The identification of successful interventions for behaviorally disordered youth is an important step in remediating preventable cycles of antisocial behavior. Furthermore, gaining an understanding of the neurobiological mechanisms of change in successful interventions is paramount in refining treatment strategies for individuals with specific vulnerabilities and needs. This research proposal aims to explore the neural underpinnings of change associated with the remarkable efficacy of a unique treatment program. The Mendota Juvenile Treatment Center, established in Madison, Wisconsin, has previously demonstrated 50% reductions in violent recidivism in incarcerated high-risk youth relative to untreated incarcerated youth. We will deploy a unique mobile MRI system to MJTC to collect structural and functional brain imaging data at multiple time points for youth involved in treatment at MJTC and matched healthy controls. This study will examine baseline neurobiological differences between groups that may provide insight into individual behavioral differences. Moreover, this proposal will examine how changes in the brain over time accompany specific outcomes such as treatment efficacy, mental health outcomes, substance abuse, and recidivism. Translational applications of this information will serve to re-inform behavioral-focused interventions in youth based on neurobiologically informed principles, identifying more efficacious, individualized treatment options.